[en] In few body physics, a major task of the resonating group method is to provide effective interactions between composite particles or clusters. These interactions contain information about the internal structure of the clusters, the forces between their constituents and most importantly about the antisymmetrization of these constituents. Conventional resonating group calculations usually span, because of so-called forbidden states, a restricted relative motion space. However, these forbidden states appear only in a very singular case. The consideration of the complete relative motion space leads to effective interactions describing the short ranged Pauli repulsion more appropriately. It is shown that this improvement may have decisive consequences in few body systems, taking the 3α system as an example. (Auth.)